A bloodbath erupted at a Dallas Cowboys watch party Sunday night in Plano when a gunman shot and killed seven people and wounded two others before police killed him. It was the largest murder scene Plano police have ever seen, according to the department. (Update: one of the wounded has died at the hospital.)

Witnesses said the shooting erupted after an argument broke out during Sunday night's game. Authorities have not yet named the victims or attacker.

A report of a "weapons call" led officers to the 1700 block of West Spring Creek Parkway. Upon their arrival, multiple gunshots erupted. Shortly after, Plano police entered the home and shot and killed an armed man.

At this point, it’s unclear how the killer knew his victims. Witnesses said they heard about 30 to 40 gunshots erupting inside the house.

"We came outside, and the next thing you know, all you heard was like, pop, pop, pop, pop, pop, pop, pop, pop," Steven Featherland told KDFW-TV (Fox 4). "That's when we both went inside."

One witness, Crystal Sugg, told reporters that the argument was between the gunman and a woman.

"As they were arguing, the woman was trying to go back in," she said. "And as she was going back in the house, you can see the man pull out his gun and just start releasing."

Plano police spokesman David Tilley seemed to be at a loss for words when he spoke with The Dallas Morning News.

“I’ve been here all my life,” he said. “I’ve never heard of anything like this.”

Christian McPhate is an award-winning journalist who specializes in investigative reporting. He covers crime, the environment, business, government and social justice. His work has appeared in several publications, including the Dallas Morning News, the Fort Worth Star Telegram, the Miami Herald, San Antonio Express News and The Washington Times.